golden_ratio.py

import turtle


def fib():
    i, j = 0, 1
    yield i
    while True:
        i, j = j, i + j
        yield i


if __name__ == "__main__":
    limit = 1_000_000
    rate = 0.001
    f = fib()

    t = turtle.Turtle()
    t.hideturtle()
    t.speed("fastest")

    # slow impl
    # n = next(f)
    # for i in range(5000):
    #     t.forward(rate)
    #     if i >= n:
    #         n = next(f)
    #         t.right(90)
    #         t.forward(rate)

    # faster impl
    t = turtle.Turtle()
    t.hideturtle()
    f = fib()

    # find sequences until limit
    for seq in f:
        if seq > limit:
            break
        t.forward(rate * seq)
        t.right(90)

    t.getscreen()._root.mainloop()
    t.done()
    # t.getscreen()
    # t.getcanvas().postscript(file="test.png")